Development Of Experimental Platform And Research On Motion Control Of Observation ROV

China has the largest number of bridges and dams in the world,many dams and bridges are submerged in water for years,the wall surface is eroded,there are many underwater concrete wall defects that are difficult to observe with the naked eye,if the defects are not detected and repaired in time may threaten the safety of people’s lives and property.Therefore,the national government spends a lot of resources to inspect the wall defects of dams and bridges every year.However,the traditional manual diving inspection method is costly,risky and inefficient.Then,the Remotely Operated Vehicle(ROV)comes into being.The main objective of this thesis is to develop an observation ROV for wall defect detection.The research work includes the following points.Firstly,reasonable operational requirements and technical indexes are formulated after investigating the field conditions.The mechanical structure of the observation ROV is designed and relevant structural strength checks are carried out according to the index requirements,and the thruster positions are reasonably arranged to make it has multi-degree of freedom maneuverability.The hardware electronic control system of the ROV is designed by module,and the functional development of the communication,image acquisition and power supply system are completed.In terms of software,the communication protocol between IPC and the STM32 controller is drawn up.What’s more,the control software of the ROV is developed in the Free RTOS operating system.Secondly,it provides the theoretical basis for the subsequent motion control research and describes the motion and force of the ROV in the fixed coordinate system.This thesis explains the principle of coordinate system transformation,derives the kinematic equations of six degrees of freedom,discusses and analyzes the forces and moments applied to ROV after coordinate transformation,and completes the dynamics modeling.The ROV control model is decoupled and simplified according to the design of the ROV and the actual working conditions in the end.Then,the motion control of the ROV is studied in order to realize the fixed-point levitation and attitude stability control.The PID control and fuzzy control algorithms are introduced,and the fuzzy PID controller is designed by combining the advantages of the two control algorithms.The parameters of the controller are optimized by using the improved particle swarm algorithm(IPSO).The algorithm and model operations are performed in Matlab and Simulink,the simulation results showed that the controller has better control effect and better immunity to external disturbances.Finally,the functionality of the ROV needs to be verified in practice,so a prototype and testbed for the ROV is built.In this process,the tightness of the sealed chamber is verified,the hardware and software of the core modules are debugged to ensure system reliability and stability.At last,the functions of the ROV are certified in the field at the pool and the water surface of road bridge.The test result is that the vehicle has the basic remote control multi-freedom maneuver,fixed-point levitation and attitude stability control,image transmission and data acquisition functions.The innovation points of the observation ROV developed in this thesis are as follows: 8 thruster vector layout is adopted,which can realize hover control of any attitude in space with stability algorithm,and has strong maneuverability,high flexibility and strong anti-turbulence ability.The designed power supply scheme can ensure the effective power supply,which does not rely on the battery power supply and greatly improves the endurance of the vehicle.In terms of motion control algorithm,fuzzy control is adopted to optimize the PID control parameters,and the improved particle swarm optimization algorithm is used to further optimize the parameters of fuzzy PID controller,which greatly improves the robustness,response speed and antiinterference ability of the control algorithm.Therefore,This thesis has a certain guiding meaning and reference value for motion control research of observation ROV,the experimental platform also has practical engineering application value.At the same time,it shows the direction for the subsequent upgrading of the vehicle,which can improve the development efficiency.